From vanderhyde at sxu.edu  Mon Mar  4 13:26:09 2019
From: vanderhyde at sxu.edu (Vanderhyde, James)
Date: Mon, 4 Mar 2019 18:26:09 +0000
Subject: alice-teacher Alice 2 "move toward" bug
Message-ID: <2FE7734C-D217-47AC-92DB-41D5BD9D62E4@sxu.edu>

I am experiencing what I think is a bug in Alice 2 in the ?move toward? instruction. See attachment. Here is the code:
  bunny move ( bunny distance to chicken ) toward target = chicken
This should move the bunny right onto the chicken, and it does, unless the chicken is moving. When the chicken is moving, even if it?s moving very slowly, the bunny does not move far enough. It should do the same thing as ?bunny move to chicken,? but it doesn?t.

I am guessing there is special logic in the implementation of ?move toward? for when the target object is moving, and there is an error in the calculation in that case. I am guessing maybe a unit vector is used instead of a vector scaled by the speed.

James
?
James Vanderhyde
Assistant Professor and Department Chair, Computer Science
Saint Xavier University
3700 W. 103rd St.
Chicago, IL 60655
773-298-3454
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.andrew.cmu.edu/pipermail/alice-teachers/attachments/20190304/bc857ae6/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: bunny move toward chicken.a2w
Type: application/octet-stream
Size: 375401 bytes
Desc: bunny move toward chicken.a2w
URL: <http://lists.andrew.cmu.edu/pipermail/alice-teachers/attachments/20190304/bc857ae6/attachment-0001.obj>

From don at alice.org  Tue Mar  5 07:13:48 2019
From: don at alice.org (Don Slater)
Date: Tue, 5 Mar 2019 07:13:48 -0500
Subject: alice-teacher Aik
In-Reply-To: <2FE7734C-D217-47AC-92DB-41D5BD9D62E4@sxu.edu>
References: <2FE7734C-D217-47AC-92DB-41D5BD9D62E4@sxu.edu>
Message-ID: <C40CD1C9-2900-44DF-8618-8E46BD2153E0@alice.org>

James,
Your world is interesting? When I built a project myself, before looking at your world, I did it with a do-together and the two moves (bunny and chicken) inside the block. Both moves had the same duration. When I ran it the chicken moved, and the bunny moved along an arc, chasing the chicken, what I assume to be the original distance of the chicken to the bunny. This made some sense to me, as the calculation of the distance in the function would be a one-time occurrence, but the concurrent moves would force some adjustment of the bunny?s path.

However, still in my world, when I adjusted the duration of the chicken move in the do-together, I saw exactly the same behavior as you illustrate in your example. An event, as I am sure you know, executes concurrently with whatever is in my first method; so our projects are very similar. The different duration periods certainly affects the behavior, but I will leave it to the support team to figure that out / explain it.

As a work around I did find that if I modified your bunny move event by adding a 

	while (distance to bunny > 0.01)
		bunny move (bunny distance to chicken) toward chicken (style abruptly)

I got the behavior that I think you were looking for?

Thank you for pointing this out.

All the best,
Don Slater

Alice Project

> On Mar 4, 2019, at 1:26 PM, Vanderhyde, James <vanderhyde at sxu.edu> wrote:
> 
> I am experiencing what I think is a bug in Alice 2 in the ?move toward? instruction. See attachment. Here is the code:
>   bunny move ( bunny distance to chicken ) toward target = chicken
> This should move the bunny right onto the chicken, and it does, unless the chicken is moving. When the chicken is moving, even if it?s moving very slowly, the bunny does not move far enough. It should do the same thing as ?bunny move to chicken,? but it doesn?t.
> 
> I am guessing there is special logic in the implementation of ?move toward? for when the target object is moving, and there is an error in the calculation in that case. I am guessing maybe a unit vector is used instead of a vector scaled by the speed.
> 
> James
> ?
> James Vanderhyde
> Assistant Professor and Department Chair, Computer Science
> Saint Xavier University
> 3700 W. 103rd St.
> Chicago, IL 60655
> 773-298-3454
> <bunny move toward chicken.a2w>_______________________________________________
> alice-teachers mailing list
> alice-teachers at lists.andrew.cmu.edu
> To change settings or unsubscribe visit:
> https://lists.andrew.cmu.edu/mailman/listinfo/alice-teachers

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.andrew.cmu.edu/pipermail/alice-teachers/attachments/20190305/94ecea86/attachment.html>

From vanderhyde at sxu.edu  Tue Mar 12 12:36:52 2019
From: vanderhyde at sxu.edu (Vanderhyde, James)
Date: Tue, 12 Mar 2019 16:36:52 +0000
Subject: alice-teacher Aik
In-Reply-To: <C40CD1C9-2900-44DF-8618-8E46BD2153E0@alice.org>
References: <2FE7734C-D217-47AC-92DB-41D5BD9D62E4@sxu.edu>
 <C40CD1C9-2900-44DF-8618-8E46BD2153E0@alice.org>
Message-ID: <0BD82A3F-0CC9-4DB3-9BC0-0587E30D005A@sxu.edu>

Don, thanks for checking. You?re right; it?s easy to set up with a do-together. The while loop does sort of solve the problem, but while loops are not one of my learning goals for this class, and neither is Zeno?s paradox!

James
?
James Vanderhyde
Assistant Professor and Department Chair, Computer Science
Saint Xavier University
3700 W. 103rd St.
Chicago, IL 60655
773-298-3454
[cid:35967E2D-3CD7-4736-B548-1ACD7307A0AD at SXU.local]
On Mar 5, 2019, at 6:13 AM, Don Slater <don at alice.org<mailto:don at alice.org>> wrote:

James,
Your world is interesting? When I built a project myself, before looking at your world, I did it with a do-together and the two moves (bunny and chicken) inside the block. Both moves had the same duration. When I ran it the chicken moved, and the bunny moved along an arc, chasing the chicken, what I assume to be the original distance of the chicken to the bunny. This made some sense to me, as the calculation of the distance in the function would be a one-time occurrence, but the concurrent moves would force some adjustment of the bunny?s path.

However, still in my world, when I adjusted the duration of the chicken move in the do-together, I saw exactly the same behavior as you illustrate in your example. An event, as I am sure you know, executes concurrently with whatever is in my first method; so our projects are very similar. The different duration periods certainly affects the behavior, but I will leave it to the support team to figure that out / explain it.

As a work around I did find that if I modified your bunny move event by adding a

while (distance to bunny > 0.01)
bunny move (bunny distance to chicken) toward chicken (style abruptly)

I got the behavior that I think you were looking for?

Thank you for pointing this out.

All the best,
Don Slater

Alice Project

On Mar 4, 2019, at 1:26 PM, Vanderhyde, James <vanderhyde at sxu.edu<mailto:vanderhyde at sxu.edu>> wrote:

I am experiencing what I think is a bug in Alice 2 in the ?move toward? instruction. See attachment. Here is the code:
  bunny move ( bunny distance to chicken ) toward target = chicken
This should move the bunny right onto the chicken, and it does, unless the chicken is moving. When the chicken is moving, even if it?s moving very slowly, the bunny does not move far enough. It should do the same thing as ?bunny move to chicken,? but it doesn?t.

I am guessing there is special logic in the implementation of ?move toward? for when the target object is moving, and there is an error in the calculation in that case. I am guessing maybe a unit vector is used instead of a vector scaled by the speed.

James
?
James Vanderhyde
Assistant Professor and Department Chair, Computer Science
Saint Xavier University
3700 W. 103rd St.
Chicago, IL 60655
773-298-3454
<bunny move toward chicken.a2w>_______________________________________________
alice-teachers mailing list
alice-teachers at lists.andrew.cmu.edu<mailto:alice-teachers at lists.andrew.cmu.edu>
To change settings or unsubscribe visit:
https://lists.andrew.cmu.edu/mailman/listinfo/alice-teachers

_______________________________________________
alice-teachers mailing list
alice-teachers at lists.andrew.cmu.edu<mailto:alice-teachers at lists.andrew.cmu.edu>
To change settings or unsubscribe visit:
https://lists.andrew.cmu.edu/mailman/listinfo/alice-teachers

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.andrew.cmu.edu/pipermail/alice-teachers/attachments/20190312/dbc0899a/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Screen Shot 2019-03-12 at 11.36.12 AM.png
Type: image/png
Size: 146316 bytes
Desc: Screen Shot 2019-03-12 at 11.36.12 AM.png
URL: <http://lists.andrew.cmu.edu/pipermail/alice-teachers/attachments/20190312/dbc0899a/attachment-0001.png>

From saleem_yusuf at hotmail.com  Sun Mar 17 23:56:43 2019
From: saleem_yusuf at hotmail.com (Mohammad Saleem Yusuf)
Date: Mon, 18 Mar 2019 03:56:43 +0000
Subject: alice-teacher Error message when running Alice 3.4
Message-ID: <CY4PR06MB2470779E0D38635FF47CDDC0EF470@CY4PR06MB2470.namprd06.prod.outlook.com>

Hello,
Once a year we hold Girls Technology Day at NHTI. This year it is on Tuesday, 3/19.
I have downloaded the latest version, created a very simple project. Sometimes it runs, but the Scene View goes blank and displays the following error message: ?rendering disabled for performance considerations?. I have high-end Dell Precision workstation with solid state drive, a high end video card and 64 GB or memory.

I am not sure why I am getting this error message. I never got this message with previous release or with projects that were created with Alice 3.2 (?)
Any help will be greatly appreciated.

Sincerely,
Saleem

Professor Mohammad ?Saleem? Yusuf
IT / Software Development
Farnum building, room 110
Phone: (603) 230-4000 x 4344

[NHTI Logo]
NHTI - Concord's Community College
31 College Drive, Concord, New Hampshire 03301



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.andrew.cmu.edu/pipermail/alice-teachers/attachments/20190318/1e4ff120/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.png
Type: image/png
Size: 14027 bytes
Desc: image001.png
URL: <http://lists.andrew.cmu.edu/pipermail/alice-teachers/attachments/20190318/1e4ff120/attachment.png>

From don at alice.org  Mon Mar 18 07:18:56 2019
From: don at alice.org (Don Slater)
Date: Mon, 18 Mar 2019 07:18:56 -0400
Subject: alice-teacher Error message when running Alice 3.4
In-Reply-To: <CY4PR06MB2470779E0D38635FF47CDDC0EF470@CY4PR06MB2470.namprd06.prod.outlook.com>
References: <CY4PR06MB2470779E0D38635FF47CDDC0EF470@CY4PR06MB2470.namprd06.prod.outlook.com>
Message-ID: <DACF500C-1C7D-4969-884D-EFD8D72BF210@alice.org>

Saleem,
Thank you for your interest in Alice and we would love to hear more about your Girls Technology Day at NHTI, when you have time.

We typically see the error you describe when students run their project, but instead of closing the run-time window to return to the code editor, they click directly on the Alice editor, moving the run-time window to the background or even hiding it. The run-time window is still in control, and the students need to bring it back into focus, close it, and then all should be well. See the attached screen capture:

	https://www.dropbox.com/s/j2apq9gw68052gw/Rendering_Disabled.mp4?dl=0

If you are seeing this under different circumstances, please let us know with any information that you think would be helpful.

All the best,
Don Slater

Alice Project

> On Mar 17, 2019, at 11:56 PM, Mohammad Saleem Yusuf <saleem_yusuf at hotmail.com> wrote:
> 
> Hello,
> Once a year we hold Girls Technology Day at NHTI. This year it is on Tuesday, 3/19.
> I have downloaded the latest version, created a very simple project. Sometimes it runs, but the Scene View goes blank and displays the following error message: ?rendering disabled for performance considerations?. I have high-end Dell Precision workstation with solid state drive, a high end video card and 64 GB or memory.
>  
> I am not sure why I am getting this error message. I never got this message with previous release or with projects that were created with Alice 3.2 (?)
> Any help will be greatly appreciated.
>  
> Sincerely,
> Saleem
>  
> Professor Mohammad ?Saleem? Yusuf
> IT / Software Development
> Farnum building, room 110
> Phone: (603) 230-4000 x 4344
>  
> <image001.png>
> NHTI - Concord's Community College
> 31 College Drive, Concord, New Hampshire 03301

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.andrew.cmu.edu/pipermail/alice-teachers/attachments/20190318/590b4cbf/attachment.html>